Automatic telephone-exchange system



A. E. LUNDELL.

AUTOMATIC TELEPHONE EXCHANGE SYSTEM.

APPLICATION man ocT. 2e. 1916.' EENEWLD MAR.6.1919.

M AM *ma @L V5 A. E. LUNDELL.

AUTOMATIC TELEPHONE EXCHANGE SYSTEM.

APELlcATloN FILED 00126. |916. RENEwED MAR. 6, 1919.

2 SHEETS-SHEET 2.

Patented May 20, 1919.

/n Ven/orf A/ben L ande/l by 'UMTED STATES PATENT onrrcn. 1 ALBEN E. LUNDELL, OF NEW YORK, N. Y., ASSIG-NOB TO WESTERN ELECTRIC COliIPANY, INCORPORATED, OF NEW YORK, N Y., A CORPORATION 0F NEW YORK.

AUTOMATIC TELEPHONE-EXCHANGE SYSTEM.'

Specification of Letters Patent.

Application led October 26, 1916, Serial No. 127,946. IRenewed March `6, 1919. Serial No. 281,070.

To all whom it may concern Be it known that. I, ALBEN E. LUNDEIJ., a citizen of the United States, residing at New York, in the county of Bronx and State of New York, have invented certain new and useful Improvements in Automatic Telephone-Exchange Systems, of which the fol v lowing is a full, clear, concise, and exact description.

This invention relates to telephone exchange systems, and more particularly to improvements in .automatic or semi-automatic telephone exchanges.

It is the object of this invention to provide a new and improved arrangement for private branch telephone exchanges, that 1s to say, for telephone exchanges in which a connector switch is adapted to seize an idle one of a plurality of lines leading to a private telephone exchange.

As well known, in Yvivate branch telephone exchanges, a plurality of lines are identified by one and the same number 1n the telephone directory. The connector switch which is set in accordance with this numerical designation of the called llne, will be stepped on to a set of terminals characterized by the called lines numerlcal de signation, and if the line terminatlng in these contacts is busy, the connector will automatically hunt for an idle line leading to the private telephone exchange. If all the lines leading to this exchange test busy, a

signal will be conveyed to the calling party and the release of the connector and other y apparatus employed in the the connection follows.

Private branch telephone exchanges are usually employed by larger bus1ness' con cerns where, after oilice hours, the private exchange is closed for traffic. It may happen, however, that it is desired to pro-- vide facilities for outside connectlons for one station, which may be either an operators position or a telephone substation. During office hours, connection may be had building up of to this telephone station by asking for it' from the operator whose position is reached by the connector. After oiiice hours, however, the private branch exchange 1s closed, and' no attempt will be made to seize the private telephone exchange.

The present inventlon provides means whereby a specially designated private branch station may be reached by dlrect means, that is to say, without regard to this, that it forms a art of a private branch exchange. This 1s accomplished by making possible the testing of a line leading to this special station, either as one of the private branch exchange lines, or as a regular direct telephone line.

The drawings diagrammatically represent a semi-automatic telephone exchange system embodying the present invention. Figure 2 should be placed to the iight of Fig. 1.

A selector switch 100, shown inl Fig. 1, and a connector switch 200, shown in Fig. 2 are of the so-called panel type, fully disclosed in Patent. N o. 1,123,696 to E. B. Craft and J. N. Reynolds. A sequence switch 101, shown in Fig. 1, is adapted to control connector switch 200 by various contacts, indicated at the right-hand side of the vertical dotted line in 1. This sequence switch may be of a similar structure' as thev one shown in a Patent No. 1,127,808 to J. N. Reynolds and C. F. Baldwin. Within a dotted rectangle in 'Fig'. l a sender is shown. A full disclosure of the circuits and controlling apparatus of such sender may be had from my Patent No. 1,168,319. In the drawing, relay 102 and a stepping relay 103 of such sender are indicated, and the description vrefers only in general terms to the operation only an upper zero counting dotted rectangle, is controlled by a sequence switch (not shown) associated with the sender, which is in turn controlled through the front` contact and armature of relay 102.

There are sequence switch contacts shown at the left-hand side of the dotted4 line in Fig. 1. These contacts, with the exception of contact 104, are controlled by a sequence switch (not shown) associated with selector 100. This sequence switch, while moving from position 1 to position 13, controls the circuits of selector 100. The detail oper-v atio'n of such selector switch is disclosed in the mentioned Patent No. 1,168,319.

A subscriber Iat. station 105, desiring to obtain a connection, removes his receiver from the switchhook, whereupon a line' relay 106 causes lthe lighting of a lamp 107. The operator, noticing this lamp lighted, in- .serts plug 108 into an answering jack 109 of the' calling line, whereupon relays 110 and 111 become energized. Relayv 110 disconnects the line relay 106 and thus causes the extinguishing of lamp 107. A calling supervisory relay 112 also becomes actuated. Relay 111 starts the sequence switch, the contacts of which are indicated at the left-hand side of the dotted line of Fig. 1. Under the control of this sequence swltch, the sender is associated with the selector 100, and in accordance with the adjustment of this sender, the selector 100 is set.

After the setting of selector 100 onto trunk terminals 113, 114 and 115, the associated sequence switch is standing in position 7, into which position it was moved by means including relay 116 operated during the setting of the selector. A circuit is closed from grounded battery, through the winding of a relayll, sequence switch contacts 117 and 118, the contact 104 of the sender sequence switch, resistance 119, the windings of the stepping relay 103, back contact and the armature of the counting relay 102, to ground. Relay 116, upon energization, moves the selector sequence switch into position 8 and'estalblishes a locking circuit for itself through its right-hand armature and front contact, and sequence switch contact 120, to ground at the armature of relay 102. A circuit is established from plus battery through` the left-hand armature and front contact of relay 116, sequence switch contact 121, selector wiper 122, terminal 113, a sequence switch contact 123, a conductor 124, and the windings of a relay 125, to minus battery. Relay 125, becomes energized and closes a circuit from plus battery, through its left-hand armature, sequence switch contacts 126 and 127, and the winding of a relay 128 to minus battery.

'Relay 128, by attracting its right-hand armature, closes a locking circuit for itself through terminal 115, wiper 129, to the plus pole of the 'battery at selector 100. Relay 128 also closes a circuit from plus battery through its left-hand armature and front contact, a contact 130, and the power magnet of sequence switch 101, to the minus :pole of battery for moving -this sequence switch out of position 1. VUnder the control of its normal spring 131, the sequence switch is moved into position 2. When the sequence 'switch 101 moves out of position 1 and opens contact 123, relay 125remains energized by a circuit closed from grounded battery, through its windings, conductor 124, sequence switch contacts 132. and 133, the right-hand front contact and armature of relay 125, a conductor 134, a sequence switch contact 135, and through the selector 100 to ground at relay 116.

In position 2 of sequence switch 101, a circuit is established from grounded battery, through the winding of a magnet 201,l

a conductor 202, sequence switch contacts 136, and 133` the right-hand front contact and armature of relay 125, conductor 134 and sequence switch contact 135 to ground through the left-hand armature and front contact of relay 116. This magnet 201, by attracting its armature, presses a brush rod 203 of the connector 200 against a roller 204, constantly rotating in the direction indicated Aby the arrow. The 'brush rod carries wipers 205, 206 and 207 and commutator brushes 208 and 209 in an upward direction. The wipers are adapted to engage the terminals of a contact bank 211. By means of a cam 206', the wipers are normally held apart and out of alinement with the terminals of 'bank 211. Commutator segments 213 and 214, provided on a plate 212, may be engaged by brushes 208 and 209 respectively.

As soon as the brush 209 engages the segment 214, ground is connected through a conductor 216, a sequence switch contact 137, conductor 138, a sequence switch contact 139, terminal 114, selector wiper 140, sequence Iswitch contacts 141 and. 120, and the right-hand armature, front contact and winding of relay 116 to grounded battery. Due to the closure of this (shunt) ath, the

relay' 103, which was energized by t e aJbove part of segment 214, relay 116 is maintained energized. lby current owing in the above traced shunt path. As soon, however, as brush 209' engages the first insulated portion -214 of the commutator segment, relay 116 becomes denergized, noves the`selector sequence switch into position 9 and opens atl i-ts left-hand contact the circuits of' relay 125 and magnet -201. Relay 125 closes a circuit from the plus pole of battery,through its left-hand armature and back contact, contacts 142 and 143 and the power magnet of sequence switch 101, to the minus pole of battery. This sequence switch is moved into position 3. Due to the dcnergizationof magnet 201, the connector is arrested in its upward travel. A circuit is now closed from the plus pole of battery, through a sequence switch contact 144, a conductor 2'17 and the winding of a trip magnet 218, to the minus pole o1 battery. The trip magnet, by attracting its armature, moves a tripv nger 219 into the path of a catch 220 which carries the cam 206.

In response to the opening of contact 104, relay 102 became denergized, and as soon as contact 104 is again closed, the originally in of relay 116. supposing that the sender is adjustedtraced circuit of relay 116s restablished. Relay 116 again locks up, moves the-selector sequence switch into position 10 and opering and closesa circuit throug is again closed and magnet 201 is thus' again operated for causin the further travel of the connector switc When catch 220 engages the .tri

219, the cam 206 is removed from etween the connector wipers and these wlpers are permitted to mjove into alinement with the terminals of bank 21'1. -Brush 208 has traveled now far enough to -engage a conducting part of commutator segment 213, and connects ground through conductor 221, Asequence switchfcontacts 145 and 139,-to the windingfo'f relay 116. Relay 103 'is then shunted out and causes the energization of the counting relay, predetermined by the adjustment of the sender. When 'brush 208 engages an insulated se ent 213', relay 103 becomes again energize The connector continues to move in an upward direction until the upper zero counting relay 102 becomes energized. Relay 116 becomes then denergize'd and moves the selector sequence switch into ition 11, and vby opening the circuit of re ay 125, causes sequence switch 101 to move into position 5. 'Magnets 218 and 201 become deenergized and the latter causesthe arrestin of the connector. f Q

pon the restablishment of the circuit of relay 116, the last or units selection fcllows. Relay 116 locks up its winding, movesthe selector sequence switch into pol sition 12, and causes the operation of relay 125, which also locks up its windin and -moves sequence switch 101 into posltion 6. In this position of the sequence switch, a magnet 222 is connected in circuit from grounded battery, through the winding ofsthis magnet, conductor 223, sequence switch contacts 146 and 133, the

ri ht-hand front contact and armature ofy relay 125, 134, 135, 113, 122, 121, .and the.

left-hand front contact and armature of relay 116 to ground. Magnet 222 presses the `brush rod against a roller 222 and causesl the movement of the connector-in -an upward direction at a lower speed than roller 204. The shunting of the stepping relay 103 is now again controlledby brush 209, connecting ground through conductor 216 and sequence switchcontact 137 to the windto cause the connector with its wipers to engage the terminals 224, 225 and 226 from which a line leads to an answering jack 231 in front of a private branch exchange. op-

erator.- After the `connector has sent back to thesender the proper numberv ofunits impulses, relay 116 becomes denergized,

,causing themovement'of the' selector sequence-switch into position 13 and the deenergization of' relay 125, .whereupon'sequenceswitch. 101 `moves into vosition 8.V

vA clrcuit 1s now closed m l ound, through the high-resistance left-hand wind;

ing of a test relay 148, sequence switch contacts; 147 ,-.the low-resistance' right-hand winding of the test relay, lsequence switch contact 149, conductor 2 27, wiper 207, terminal 226, and the winding of..a` relay 228, to theplus pole of grounded battery. The .relay 148 is marginaln its operatlon and will not pull up unless, full battery potential is applied through a resistance eflOO ohms to the test-terminal 226. The winding of relay 228 is of `a resistance of .100 ohms, and therefore'in the present case relay 148 becomes energized and 'closes a circuit from 'the plus pole of battery, through its lefthand armature and front contact, a contact 150 and the power magnet of sequence'.

switch 101, to the minus polel of battery. The sequence switch is movedinto position 10. By attractlng its right-hand armature relay 148 shunts out its'high-resistance lefthand' windin and locks up through its lowresistance rig -hand winding in series with relay 228. Relay 228, which does not become 'i l energizedvin series with both vwindings of the test relay, -now becomes energized.

Other .connectors attempting to seize these.

terminals will connect through their test brush, corresponding to 207,a reduced Ebattery potential to their, .test relays, whereby the energization of such test relays is prevented.

j 'When the sequence switch 101 .passes through position 9, a circuit is closed from" ground, thro-ugh sequence switch contacts 151.

and 152, and the right-hand winding of a differentially wound relay 153, to the plus pole of 'grounded battery. 'The circuit of the lefthand winding of relay 153 being open vthe right-hand back contact of'relay 148, only one. winding .(the right-hand winding) of relay 153 is energized, and therefore this relay attracts its armature. The purpose of relay 153 will appearf from the further de'- scription of the system. When sequence switch 101 reaches position 10, relay 125 being denergized, a circuit is closed from the plus pole of battery, through .the left-hand armature and back contact of relay 125, contacts 142 and 143,

and the lpower magnet of sequence switch 101, to the minus pole ofbattery, and this sequence switch is moved out of position I i 10 and into position 14.` In' position 14 of 'quencel switch-contact 150 and the magnet of sequence'switch 101 is again closed, and thus the sequence switch is moved into position 16, which is the talking position. The private branch exchange operator is now signaled in any well-known manner, for 1nstance,- by sending alternating current l through the winding of a 'relay 251, condesired connection, e` g.,- to station 245, by

troliing a drop signal 252. The privatev branch. exchange operator establishes the means of her cord circuit 253 known manner.

If the line terminating in contacts 224, 225 and 226 is busy, then the test relay 148 in the wellv does notbecome energized. The potential 228 in a circuit through a similar test termi'l tending through the sleeve contact of a jack on test termi-nal 226 may belowered in the above described manner by including relay nal of another connector, or in a circuit eX- lof relay 125, to the minus pole of battery.

Relay 125, by, attracting its left-hand armature, causes the movement of sequence switch 101 out ofposition 8 and into position l10. 1n position 10 of the sequence,

switch, a circuit is closed from grounded battery, through the winding of magnet 222, conductor 223, sequence switch contacts 146 and 133, the right-hand armature and front contact of relay 125, conductor 134, and a sequence switch contact 156, to ground. Magnet 222 tlius again becomes energized and causes the further travel of the con-- nector switch. As long as brush 207 passes over terminals like 226, an energizing circuit is maintained from ground, through the right-hand amature and bacl contact of relay 148, the left-hand winding of relay 153, sequence switch contact 157, conductor 227, wiper 207, terminal 226, and the winding of a relay-like 228, to the plus pole of grounded battery. In view of the f'act that in position 10 of the sequence switch the right-hand winding of relay 153 is also energized, this relay does not pull up its armature. As soon as the test wiper 207 engages a'terminal 226, on which full battery potential exists, relay 4148 becomes energized.

' Relay 148 opens at its left-hand back contact the circuit of relay 1 25, and at its righthand'back contact, the circuit including the left-hand winding of relay 153. Relays 153 Lacasse and 125 become' denergized, and the latter causes sequence switch 101 to move out of position 10 and into position 14, from which position it is moved into position 16 by a circuit closed at the left-hand front contact of relay 148, as previously described.

Supposing that all the. lines leading to this private branch exchange' are busy, that is to say, the test contacts individual to such lines are connected through a relay like 228 to the positive pole of battery, the potential of which has been reduced. The test terminal 260 of the last private branch .exchange \line is connected through a 100-ohm resistance 261, which in practice may comprise a resistance like 229 and a relay like v230, to the minus pole of grounded battery. When wiper 207 engages this terminal, the current flowing through the left-hand winding of relay 153 is not ofthe proper direction to maintain it energized." This relay, therefore, under the control ofk its righthand winding, pulls up its armature under the control of itsright-hand winding, and. by opening the circuit f relay 125, causes the movement of sequence switch 101 out of position 10 and into position 14. If full attery potential exists on terminal 260, then the line is seized in the same manner as above described. If, however, the potential` tion 10, the circuit through the right-hand winding of. relay 153 isV opened, and this relay becomes denergized. If, as in the present case, the sequence switch 101 rests in position 14,a circuit is closed from the minus pole of battery, through the winding of a magnet 231, Vconductor 232, sequence switch contacts 160, the left-hand back contact andI armature of relay 148, to the plus pole of battery.` Magnet 231 presses the brush rod against a roller 233, constantly lrotating in the direction -indicated by the arrow, whereby the connector is restored to its normal position. As soon as the connector reaches the normal position, a cir cuit is closed from ground through the brush 208, a conducting segment 234, conductor 235, a contact 165 and the power magnet of sequence switch 101, to grounded battery, whereby this sequence switch is moved through position 16, into position 17. 1n position 17 a circuit is vclosed from ground through the secondary winding of an induction coil 161, sequence switch contacts 162, conductor 163, and through terminal`114 and wiper 140 to the connecting operators telephone set (not shown). A busy tone apparatus is inductively connected tov this secondary winding 161, and therefore the connectin operator will be informed that the line is busy. She then causes the release of selector 100 by any well-known means. As soon as the wiper 129 leaves terminal 115, the locking circuit of relay 128 is opened. This relay, upon deenergization, closes a circuit from the plus lpole of battery, through its left-hand armature and back contact, a contact 164, and the'power magnet of sequence switch 101 to the minus pole of battery. This causes the movement of the sequence switch out of position 17 and into position 18, whereupon the sabove described circuit through brush 208 is again closed and sequence switch 101 is moved out of position. A

If, after the successful 'establishment of a connection, the subscribers desire disconnection, then by hanging up their receivers they may cause the denerglzation of supervisory relays 112 and 166. The connecting operator, noticing the clearing-out signal, causes the release of selector 100, whereupon relay 128 .becomes denergized and 'closes .through its left-hand armature and back contact a circuit for moving sequence switch 101 out of position 16 and through position 17 into position 18.' A circuit is then closed forA the release magnet 231 from the plus pole of battery, through sequence switch contacts 167 and 168, and when brush 208 engages conducting segment 234, the selector 101 is moved out of position 18 into position 1, opening thus the circuit of the release magnet 231.

1f it is desired to make possible the direct seizure of a private branch exchange line, such as the line leading to station 245, then this subscribers station is connected by means of the private branch exchange operators cord circuit 253 to Ia trunk leading -to some other connector terminal than a private branch exchange terminal, e. g., terminals 224 and 225'.

The connector 200, when operated in accordance with any number designating a private branch exchange, seizes the line designated, if such line is idle. If, however, the designated line is busy, the connector automatically hunts for an idle line leading to the private exchange. As shown in Fig. 2, .the private branch exchange line terminating in contacts 224, 225 and 226 and multiples thereof, is multipled to connector Aterminals 224', 225' and 226'. The connecting operator may adjust her sender to control the setting of the connector on to the terminals t position 18 into its normal.

224', 225', 226', Will be rejected because of the low-resistance path closed to test terminal 226 through the low-resistance righthand Winding of test relay.148.

' In order to prevent the actuation of relay 230, in response to the energization of relay 228, the relay 228 closes at its inner front of relay 230. It will be noted'that if the line terminating in jack 250 is seized through the branch ,leading to terminals 224, 225 and 226, the,

relay 228 is actuated, and if this line is seized Contact a short circuit around the winding l through the branch leading ,to terminals 224', 225' amd 226', the relay 230 is actuated. Relays 228 and 230 are individual to the line, and serve to cut oil? the line relay 241 if the line is seized, as a calling or'called line. 1f the inner front contact of cutoff relay 228 was not connected to the winding of cutofl" relay 230, then, upon the energization of the former relay` a circuit would be established from ground through the outer armature and back contact of relay 230, the outer armature -and front contact of relay 228, resistances 243 and 249 and theA winding of relay 230 to grounded battery. This energizing circuit being controlled at the back contact of relay 230 would cause the latter to buzz` and would render impossible the testing of the line at-226.

If it is desired to initiatea call from st athe switchhook at that station; relay 270 be- `comes energized and actuates a signal 271 at the private operators position, who then, by means of her cord circuit 253, establishes the desired connection.

If the station 245 is permanently' connected for outside connections in theabove described manner, then upon the removal of the receiver, a circuit is established from grounded battery, through the. -inner armature and back contact of cuto'l" relay 230, the inner armature and back contact of cutoff relay 228, the winding of a line relay 241, the apparatus at station 245, the outer backcontact and armature of relay 228, and the outer back contact and armature of relay 230, to ground. Relay 241 closes a circuit 'from ground through itsfront contact and armature, and a lamp 242, to grounded battery, for attracting the connecting operators attention. When this operaton inserts a plug such as 108 in the answering jack 231 of station 245, relay 228 becomes energized,

. opens the circuit of relay 241, and thus causes the extinguishing of lamp 242. A circuit is also closed from ground through the outer armature and back contact of relay v230, the outer armature and front contact and, therefore, the test relay of the connector cannot become energized.

What is claimed is:

l. In a telephone exchange system, a plurality of lines, means for renderingA any one of said lines busy, a switching deyice operable to engage any one of said lines when idle, automatic means operative upon the engagement of a busy line by said device for causing it to successively engage. the other lines, releasing means for said deviceoperated upon the engagement of the last line if such line is busy, and'means operative upon the engagement of a certain one of said lines for preventing the operation of said automatic means.

2. In a telephone exchange system, a plurality of lines, means for rendering any one of said lines busy, a selectively operable switching device, means for operating said switching device to engage one of said lines, automatic means operative thereupon if said line is busy for causing said switching device to successively engage the other lines, a releasing means for said switching device operated thereupon if the last one of said v lines is busy, and means for operating said releasing .means upon the engagement by said device of another line than the last line if such line'is busy.

'3. In a telephone exchange system, a line, a plurality of test contacts therefor, means for causing said line to test busy at all of said test contacts, a selectively operable switching device, means for causing it to engage any one of said test contacts, a normally inactive releasing means for said de-` vice operated in response to the engagement of one of said busy test contacts by the device, and means for maintaining said releasing means in its normal condition if said device engages another one of said busy test contacts.

l4.. In a telephone exchange system, a selectively operable switching device, a line,

a plurality of contacts :for said line, a seriesvv of other contacts, said contacts being arranged for engagement Vby said switching Acausing said switchin device to engage one of the contacts of sai line, automatic means operative if said last-mentioned contact-tests busy for causing said switchin devicelv to successively engage said series o other contacts, a releasing means for said device operated upon the en agement of the last contact in the series i such contact tests` busy, and .means for operating said releasing means in response to the engagement of another contact of said line if such contact tests busy. l

5. In a telephone exchange system, a plurality of lines, two calling test terminals for one of said lilies,- one calling test terminal for each one of the other lines, a selectively operable switching device, means for rendering any one of said lines busy,'means for operating said device to test said one of said lines at one of its test terminals, means operative thereupon 'and controlled by the busy condition of said line for causing said device to test said other lines at .their terminals until an idle one is found, releasing means for said switching device operated if all said other lines test busy, means for causing said switching device to test said one ofsaid lines at the other of its test terminals, and means operative thereupon if said line is busy .for actuating said releasing means.

6. In a telephone exchange system, a line, two test contacts for said line, two relays, one connected to each one of said test contacts, and means controlled by one of said relays for preventing the other relay from operating. l

7 In a telephone exchange system, a line, a plurality of branches therefor, aswitching device for seizing said line through any one of said branches, two cutoff relays for said line, means for actuating one of said relays upon the seizure of the line through one branch and the other relay upon the seizure of the line through another branch, and

means operative upon the actuation of one of said relays for preventing the other one from operating.

8. In a telephone exchange system, a connector switch, a plurality of private branch exchange lines terminating at said connector 1916. ALBEN E. LUNDELL.

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